German Published Patent Application No. 21 46 625 and German Patent No. A-20 03 076 describe high-voltage metal-cladded switchgears in which the power switch and the respective busbar are insulated from the isolating switches when the isolating switches are in isolation mode. Closing an isolating switch establishes a conducting connection with the power switch as well as the respective busbar conductor in a relatively complicated manner. The potential of the isolating switches is indeterminate in isolation mode. This can lead to sparkover.
Furthermore, the isolating switches, which have a few moving parts, are susceptible to problems and it is impossible to guarantee with certainty that both isolating switches are always connected to the power switch.
A similar high-voltage switchgear is known from European Patent No. 0 348 313, for example. With the known switchgear, two busbars are provided with isolating switches whose terminals project into the gas space of a power switch, where they are connected using a connecting conductor. The power switch is connected to the connecting conductor.
With this embodiment, assembly and dismantling are very tedious, because the connecting conductor must be connected to the terminals of the isolating switches or disconnected from them again.
European Patent No. A-0 152 611 describes a high-voltage switchgear with a power switch that can also be connected to two isolating switches.
The power switch described there, however, cannot easily be removed from its enclosure, which is separated from the enclosure of the isolating switches and the busbars, without opening the isolating switch enclosure. To remove the power switch, part of its enclosure must also be removed.
The European Patent No. A-0 152 611 also describes a plug-and-socket connection for contacting an isolating switch that is in the gas space of the isolating switches there, which results in the fact that the enclosure of the power switch must be removed to separate the connection between the power switch and one isolating switch.